Minimally invasive apparatus for implanting a sacral stimulation lead

Abstract

Methods and apparatus for implanting a stimulation lead in a patient's sacrum to deliver neurostimulation therapy that can reduce patient surgical complications, reduce patient recovery time, and reduce healthcare costs. A surgical instrumentation kit for minimally invasive implantation of a sacral stimulation lead through a foramen of the sacrum in a patient to electrically stimulate a sacral nerve comprises a needle and a dilator and optionally includes a guide wire. The needle is adapted to be inserted posterior to the sacrum through an entry point and guided into a foramen along an insertion path to a desired location. In one variation, a guide wire is inserted through a needle lumen, and the needle is withdrawn. The insertion path is dilated with a dilator inserted over the needle or over the guide wire to a diameter sufficient for inserting a stimulation lead, and the needle or guide wire is removed from the insertion path. The dilator optionally includes a dilator body and a dilator sheath fitted over the dilator body. The stimulation lead is inserted to the desired location through the dilator body lumen or the dilator sheath lumen after removal of the dilator body, and the dilator sheath or body is removed from the insertion path. If the clinician desires to separately anchor the stimulation lead, an incision is created through the entry point from an epidermis to a fascia layer, and the stimulation lead is anchored to the fascia layer. The stimulation lead can be connected to the neurostimulator to delivery therapies to treat pelvic floor disorders such as urinary control disorders, fecal control disorders, sexual dysfunction, and pelvic pain.

1. A surgical instrumentation kit for minimally invasive implantation of a sacral stimulation lead through a foramen of the sacrum in a patient to electrically stimulate a sacral nerve, the sacral stimulation lead of the type having a lead body extending between a lead body proximal end and a lead body distal end, the lead body having a lead body diameter extending from the lead body proximal end and lead body distal end, the lead body further enclosing at least one electrical conductor extending between at least one proximally located electrical connector adapted to be coupled to an electrical stimulation pulse generator and at least one distally located stimulation electrode adapted to apply electrical stimulation to a sacral nerve, the kit comprising:
 a sacral stimulation lead; and  
 a needle having a needle diameter and needle length extending from a needle distal end capable of penetrating body tissue and a needle proximal end, the needle adapted to be grasped by a medical clinician with the needle distal end directed toward and inserted through an entry point of the skin or a skin incision posterior to the sacrum and guided along an insertion path into a foramen to locate at least a distal portion of the needle extending alongside a sacral nerve and a proximal portion of the needle extending from the entry point away from the patient's skin; and  
 a dilator having a dilator body diameter, a dilator body length extending between a dilator proximal end and a dilator distal end, and a dilator body lumen extending from the dilator proximal end to the dilator distal end and having a dilator body lumen diameter sized in operative relation to the lead body diameter and the needle diameter to selectively receive the needle and the lead body therein,  
 wherein the dilator is adapted to be inserted over the needle proximal end to locate the needle within the dilator body lumen and to be advanced distally over the needle through the insertion path to dilate the insertion path to the dilator diameter, the needle is adapted to be withdrawn through the dilator body lumen, the stimulation lead is adapted to be advanced through the dilator body lumen to locate the stimulation lead electrode into operative relation to the sacral nerve, and the dilator is adapted to be withdrawn over the stimulation lead body,  
 wherein if the needle proximal end comprises a hub, the hub is cut off prior to inserting the dilator over the needle proximal end,  
 wherein the needle body comprises depth marks enabling visualization of the depth of insertion of the needle through the insertion path,  
 wherein the dilator body comprises depth marks, and  
 wherein the needle body depth marks correlate to the dilator body depth marks so that the depth of insertion from the skin of both the needle body and the dilator is ascertainable from an exposed needle body depth mark and an exposed dilator body depth mark.  
 
   
   
     2. The kit as in  claim 1 , wherein the needle further comprises an electrically conductive needle body providing a distal electrical stimulation electrode end and a proximal electrical connector, the needle body electrically insulated in a region grasped by the medical clinician between the electrical stimulation electrode and electrical connector, whereby the distal needle body location in relation to a sacral nerve can be assessed by delivering electrical stimulation through the needle to evoke a patient response signifying the distal needle body location. 
   
   
     3. The kit as in  claim 1 , wherein the needle diameter is in the range from about 0.46 mm to about 2.80 mm. 
   
   
     4. The kit as in  claim 1 , wherein the dilator diameter is in the range from about 0.33 mm to about 4.00 mm. 
   
   
     5. The kit as in  claim 1 , wherein the needle is selected from the group consisting of a needle without a hub, a needle with a removable hub, a solid rod with a sharp tip, and a foramen needle. 
   
   
     6. The kit as in  claim 1 , further comprising an anchor selected from the group consisting of a suture anchor and a twist-lock suture anchor for anchoring the stimulation lead to the fascia layer upon withdrawal of the dilator over the stimulation lead body. 
   
   
     7. A surgical instrumentation kit for minimally invasive implantation of a sacral stimulation lead through a foramen of the sacrum in a patient to electrically stimulate a sacral nerve, the sacral stimulation lead of the type having a lead body extending between a lead body proximal end and a lead body distal end, the lead body having a lead body diameter extending from the lead body proximal end and lead body distal end, the lead body further enclosing at least one electrical conductor extending between at least one proximally located electrical connector adapted to be coupled to an electrical stimulation pulse generator and at least one distally located stimulation electrode adapted to apply electrical stimulation to a sacral nerve, the kit comprising:
 a sacral stimulation lead; and  
 a needle having a needle diameter and needle length extending from a needle distal end capable of penetrating body tissue and a needle proximal end, the needle adapted to be grasped by a medical clinician with the needle distal end directed toward and inserted through an entry point of the skin or a skin incision posterior to the sacrum and guided along an insertion path into a foramen to locate at least a distal portion of the needle extending alongside a sacral nerve and a proximal portion of the needle extending from the entry point away from the patient's skin; and  
 a dilator having a dilator body diameter, a dilator body length extending between a dilator proximal end and a dilator distal end, and a dilator body lumen extending from the dilator proximal end to the dilator distal end and having a dilator body lumen diameter sized in operative relation to the lead body diameter and the needle diameter to selectively receive the needle and the lead body therein so that the dilator is insertable over the needle proximal end to locate the needle within the dilator body lumen to be capable of being advanced distally over the needle through the insertion path to dilate the insertion path to the dilator diameter and to allow the needle to be withdrawn through the dilator body lumen and to allow the stimulation lead to be advanced through the dilator body lumen to locate the stimulation lead electrode in operative relation to the sacral nerve and to allow the dilator to be withdrawn over the stimulation lead body,  
 wherein if the needle proximal end comprises a hub, the hub is cut off prior to inserting the dilator over the needle proximal end,  
 wherein the needle body comprises depth marks enabling visualization of the depth of insertion of the needle through the insertion path,  
 wherein the dilator body comprises depth marks, and  
 wherein the needle body depth marks correlate to the dilator body depth marks so that the depth of insertion from the skin of both the needle body and the dilator is ascertainable from an exposed needle body depth mark and an exposed dilator body depth mark.  
 
   
   
     8. The kit as in  claim 7 , further comprising:
 means for creating an incision through the entry point of the epidermis to a fascia layer;  
 means for anchoring the stimulation lead to the fascia layer upon withdrawal of the dilator over the stimulation lead electrode; and  
 means for closing the incision.  
 
   
   
     9. The kit as in  claim 7 , wherein the needle further comprises an electrically conductive needle body providing a distal electrical stimulation electrode and a proximal electrical connector, the needle body electrically insulated in a region grasped by the medical clinician between the electrical stimulation electrode and electrical connector, whereby the distal needle body location in relation to a sacral nerve can be assessed by delivering electrical stimulation through the needle to evoke a patient response signifying the distal needle body location. 
   
   
     10. The kit as in  claim 7 , wherein the needle diameter is in the range from about 0.46 mm to about 2.80 mm. 
   
   
     11. The kit as in  claim 7 , wherein the dilator diameter is in the range from about 0.33 mm to about 4.00 mm. 
   
   
     12. The kit as in  claim 7 , wherein the needle is selected from the group consisting of a needle without a hub, a needle with a removable hub, a solid rod with a sharp tip, and a foramen needle. 
   
   
     13. The kit as in  claim 7 , further comprising an anchor selected from the group consisting of a suture anchor and a twist-lock suture anchor for anchoring the stimulation lead to the fascia layer upon withdrawal of the dilator over the stimulation lead body.